OBD-II code · Powertrain (generic)
P0240 Turbocharger/Supercharger Boost Sensor B Circuit Range/Performance
Boost pressure sensor B reading implausible. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
Is it safe to drive with P0240?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor reading drifted
- Less likelySensor element aged beyond calibration window
- Less likelySensor mounting loose - signal damping
Symptoms
- Check engine light on
- Significant power loss / limp mode
- Possible blue or black smoke from exhaust
- Whistling or hissing sound from intake
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Boost Pressure Sensor B
Related codes
- P25F3Turbocharger/Supercharger Boost Sensor C Circuit Range/Performance
- P2CD7Turbocharger/Supercharger Boost Sensor D Circuit Range/Performance
- P023DManifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor A Correlation
- P023EManifold Absolute Pressure - Turbocharger/Supercharger Boost Sensor B Correlation
- P023FFuel Pump Secondary Circuit/Open
- P0241Turbocharger/Supercharger Boost Sensor B Circuit Low
- P0242Turbocharger/Supercharger Boost Sensor B Circuit High
- P0243Turbocharger/Supercharger Wastegate Actuator A
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.